Objectives: Social and economic status (SES) does not have the same societal implications and health consequences in different periods of time. It has been hypothesized that persons in lower SES are relatively more disadvantaged recently than in prior decades, that not all segments of society have benefitted from increased living standards, and that as a consequence, the mortality gap between rich and poor has increased. Thus, the relationship between social and economic factors and death and disease may not be static, and needs evaluation and reassessment as these conditions change. Results from existing national studies are applicable only to the time frame in which the data were collected. To gain an understanding of the powerful and changing influence of socioeconomic status, contemporary studies need to be undertaken.